Costs per child

Does anybody know how much material you use on one facepaint?

A school nearby asked me to paint at their yearly fair. They have no money to hire me, but offered me to pay the costs of the material. I have no experience other than our own school so I have never had to think about the costs.

I would just charge them a flat $50 or so for materials.....you won't use that much in materials, but it will also buy you a nice meal afterwards for your time.

It's not that recise; charge them for a few cakes, sponges and brushes, as said.
The most popular, ie pink, white, black, red....
Cat x

what you could do is buy an 8 colour pallette and some sponges, charge them for that and they can keep it afterwards for another event? You could still bring some of your extras if you like, to make your selection better, but the only way I do things like that is that for charity events I charge half my normal rate... it's still a heck of a deal considering I still go in full clown (for the exposure).